Flotation of ores



Patented Feb. 17, 1953 FLOTATION or ones Robert Ben Booth, Springdale,Conn., and John Vivian Hill, Tucson, Ariz., assignors to AmericanCyanamid Company, New York, N. Y., a corporation of Maine No Drawing.Application June 25, 1947, Serial No. 757,058

8 Claims. 1

This invention relates to a new process -mi--- floating metal ores. Basemetal and precious metal ores, particularly of the sulfide type, havebeen floated in the past in the main by three types of reagents. Thefirst group is the x anthates, the second the dithiophosphates, to alesser extent thiocarbanilides and similar reagents have been used.While the standard flotation promoters for sulfide minerals giveexcellent results with the general run of ores, there is room forimprovement, particularly with some ores containing both sulfide andoxide metal values. esses of floating metal ores, particularly thosecontaining some sulfides, with a new class ofiprbmoters. These promotersare reaction products of glycol chloroformates with one or two mols ofxanthates. The reaction proceeds by a simple mixing of the reagents atroom temperature. The compounds appear not to be completelypure chemicalcompounds in some cases and are probably mixtures. Furthermore, mixturesof two or more xanthates may be used in the reaction. Without limitingthe invention to any precise chemical formula for the promoters, webelieve it probable that at least a major constituent of The presentinvention deals with procthe promoters have the following formulae: v

the first applying to products in which one mol of xanthate is reactedwith the chloroformate and the second where two mols are so reacted.

In the formulae, one of the simplest glyc'o'ls'fdiglycol, is used forillustrative purposes.

The in-:

vention, however is not limited to the use of renew chemical compoundsas they form the subject matter of the co-pending application of-Boothand Light, Serial No. 757,057 filed June 25, 1947 concurrently herewith.

The amount of reagent used with typical ores is of the same orderofmagnitude as is the case with xanthates, namely a few hundredths of alimited to some extent.

pound per ton. Other flotation conditions are substantially the same aswhen xanthates or dithiophosphates are used. This is an advantage of thepresent invention as ordinary flotation circuits and conditions do nothave to be changed in any material way. The novelty of the process ofthe present invention lies in the use of a new class of promoters.

While it is not essential that the ore be conditioned with the promoterbefore flotation, we find that with many ores this procedure is deesirable. Here again the use of the new promoters does not materiallychange good flotation prac tice.

' Although, as has been stated above, we believe that the promoters. ofthe present invention are not always pure chemical compounds but oftenconstitute mixtures, it is definitely proven that the improved resultswhich are obtainable with many ores by following the procedure of thepresent invention are not due to unreacted chloroformate, as thisappears to have extremely poor collecting power.

In the following specific examples, comparative tests with standardreagents are given. It should be noted that the flotation art,particularly with ores containing sulfides, has reached so high a stateof development that improvements are The present invention does improveto a substantial extent-the re.- coveries obtainable. Particularly withlowgrade ores, the amount of mineral available is small and highrecovery becomes essential in order to keep the process within economiclimits. The improvement which is obtainable in recovery when the processof the present inventionis. used is, therefore, an important economicfactor and per,- mits a substantial lowering in cost with many ores.

Example 1 A copper ore from the southwestern United States containingvarious sulfide and oxide cop.- per minerals and assaying about 0.90%Cu, was ground with lime and promoter at solids, diluted to 22% solids,and conditioned with 0.072 lb./ton pine oil. Flotation followed for 6minutes in a Fagergren type flotation machine. A

series of tests using DBL-0.025. lb./ton reaction products of 1 mol ofxanthate and 1.mol of diglycol chloroformate were conducted. Also for 3purpose of comparison, tests were conducted with certain of the startingingredients of these reaction products, viz., diglycol chloroformate,sodium ethyl xanthate, and potassium amyl xanthate. Metallurgicalresults follow:

erals was ground at 60% solids, diluted to 22% solids, conditioned for 2minutes with 5.0 lb./ton sulfuric acid and then 1 minute with 0.21lb./ton cresylic acid, and floated for 8 minutes in a Fagergren typefloating machine. The collectors were It will be noted that glycolchloroformate even in much larger amounts is not a useful collectoradded to the grind in these tests. Metallurgical results follow:

Collector Used Concentrate 'Iailing Assay, v Assay, Percent Reaction Iiorluct lb./tou Percent Permit Cu 2 mol Sodium Ethyl Xanthate 1 molDiglycol Ghloroformatc 1 890g (1 mol bodium Ethyl Xa'ithate)... (1 molPotassium Aim-l Xanthate) 0.1 18.0l 89. 32 0. 28 1 mol DiglycolChloroforn'ate even in comparison with the xanthates themselves. These.latter gave results which Were not as good as is obtainable with theprocess of the present invention, but of course of an entirely differentorder of magnitude than the chloroformate itself which cannot properlybe considered as a practical promoter.

Example 2 A copper ore from the southwestern United States, generallysimilar to that used on Example 1. was ground with lime and floated with0.025 lb./ton of the reaction products of 2 mols sodium isopropylxanthate or sodium secondary butyl xanthate with 1 mol diglycolchloroformate and 0.07 lb./ton pine oil as frother. A comparative testwas run with 0.025 lb./ton of a technical grade disecondarybutyldithiophosphate, the standard reagent on this ore. Metallurgicalre- Example 4 A zinc ore from the southeastern United States was groundand conditioned with 0.5 lb./ton copper sulfate, 0.015 lb./ton of thereaction product of 1 mol of sodium ethyl xanthate and 1 mol of diglycolchloroformate, and 0.14 lb./ton pine oil. Flotation followed for 4minutes with an additional 0.04 lb./ ton pine oil added after 2 minutes.From a feed to flotation, assaying 3.07% Zn, 92% of the total zinc wasrecovered in a concentrate assaying 54.88% Zn. The flotation tailingsassayed 0.25% Zn,

Example 5 A Tri-State lead ore containing mainly galena but also someoxidized lead minerals was ground and conditioned with 0.02 lb./ton ofthe reaction sults follow: P oduct of 1 mol of sodium ethyl xanthate and1 I Concentrate,

Percent Cu Tailing G ollector Used-Reaction Product I v Distri- Cu Assaybution 2 mol Sodium isopropyl xanthate 1' mol llgillyenlchlsrol'oriat%h..t..... 51 21 2 mol Otassium my an a e 1 mol Diglycolchloroformate. 92 50 20 Disco. butyldithiophosphate (alone) 16. 96 75.()4 0.25

It will be noted that a substantial reduction in the copper content ofthe tailings was obtained with the above-listed reaction products ascompared to the standard dithiophosphate reagent used on this ore.

Example 3 A South American copper ore containing about 2.3% Cu as bothsulfide and oxidized copper minmol of diglycol chloroformate and 0.18lb./ton

creosote oil. The ground pulp was diluted to 22% solids, conditioned for0.5 minutes with mixed amyl alcohols as frother, and floated 4 minutes.From a feed to flotation assaying 2.76% Pb, 81.60% of the total lead wasrecovered in a concentrate assaying 53.73% Pb. The assay of the tailingwas 0.53% Pb.

Example 6 Because of their high stability reagents of this in which R isan alkyl radical and Z is a radical selected from the group consistingof C1 and type are suited especially to flotation in acid cir- CO cuits,particularly the high acid concentrations 1.! used in the recovery ofcopper by the leaching-- 5 precipitation-flotation process. Metalliccopper The melfihnd collcentratmg sulphlde Ore is readily floated bythese promoters either in the Whlch comm 159s sumeclnng the i form ofpresence or absence of sulfide minerals as is coma pulp to fmthfio?atlor Opemmon the pres moninleachmrecipitatien practica ence of acompouno having the structural for- A southwestern copper ore containing1.29% 10 mum: total copper (0.82% sulfide copper and 0.47% ORnon-sulfide copper) was ground and leached with I l sulfuric acid at apH of 1.5. The pH Was adjusted T fi fi if to about 2.8 by addition oflime and the dissolved S 0 0 8 pp r precipitated y means f iron- The inwhich R. and R." are alkyl radicals. pre p ant was screened from the oreP p 3. A method of beneficiating metallic ores Which to t er With e p pd Copper Was which comprises subjecting the ore to froth flotap d t &rgren flotation machine, brought tion in the presence of a promoterhaving as an 170 0 DH of about 5 by addit o of l e, Conditionedessential promotin constituent a compound of with 0.033 lb./ton pine oiland 0.05 1b./ton of the th f 1 reaction product of 2 mol ethyl Xanthateand 1 mol diglycol chloroforrnate and floated 10 minutes to produce acombined concentrate of copper C-SOOO2H4O C2H4O O-01 sulfides andmetallic copper. The tailings from H [I H the flotation operationassayed 0.06% total copper and 0.03% non-sulfide copper. About 95% of inWhlch R is an alkyl Tadlcalthe copper was recovered 4. A methodaccording to claim 2 in which the ore is a copper ore containingsulfides of copper. Example 7 5. A method according to claim 3 in whichthe A copper ore (about 0.95% Cu) from the ore is a copper orecontaining sulfides of copper. southwestern United States, containinchal- 6. A method according to claim 2 in which the copyrite, bornite,pyrite, pyrrhotite, iron oxides, ore is a zinc ore. quartz, carbonatesand silicates was ground with 7. A method according to claim 3 in whichthe the collector and lime, conditioned at flotation ore is a zinc ore.density with 0.07 Ila/ton pine oil, and floated for 8. A methodaccording to claim 2 in which the 6 minutes. Reaction products ofvarious glycol ore is a lead ore. chloroformates (1 mol) Xanthates (2mols) were ROBERT BEN BOOTH. used as collectors. Metallurgical resultsfollow: JOHN VIVIAN HILL.

Concentrate Telling, Xauthatc 2111015 Ohloroformate ofg-gig Percent 5 5Cu Distr. Assay Assay Sodium Ethyl Ethylene Glycol "0.019 17.20 82. 26"0.18 Sodium Isopr0pyl do 0.018 14. 66 83.31 0.17 Potassium Amy1 d0 0.01917.20 84.48 0.15 Sodium Isopropyl Dipropylenc GlycoL. 0.018 15.66 82.410.17 D Trimethylene Glycol 0.019 16. 43 83.16 0.17 Octadecanediol 0.02718.63 77.19 0.23 Trieihylene Glycol 0.021 16.32 81.39 0.18 2Metl1yl,24Pentanedio1.. 0.013 18.96 76.70 0.22 213110 11624 cliol 0. 020 20. 510.20 rDiglycol 0.019 10.45 82.52 0.17 Sodium Sec. Butyl (1 mol) ..(lo0.018 15. 79 82.63 0.17

i t t CITED The following references are of record in the file of thispatent:

UNITED STATES PATENTS Number Name Date 1,652,099 Douglass Dec. 8, 19271,684,536 Fischer Sept. 18, 1928 2,048,043 Williams July 21, 19362,070,634 Werntz Feb. 16, 1937 2,376,242 Fischer May 15, 1945 2,501,269Fischer Mar. 21, 1950

1. A METHOD OF BENEFICIATING METALLIC ORES WHICH COMPRISES SUBJECTINGTHE ORE TO FROTH FLOTATION IN THE PRESENCE OF A PROMOTER HAVING AS ANESSENTIAL PROMOTING CONSITUENT A COMPOUND OF THE FORMULA: